SIGNAL AND DISPATCHING SYSTEMS

Kg. 82 illustrates a semaphore signal manufactured by the
General Railway Signal Company. In two-position signaling,
the semaphore when in a horizonal position indicates "danger/'
while the "proceed" or "clear" signal is usually indicated by
a 60 deg. angle from the horizontal.

As the train arrives at the entrance of a block the home signal
denotes the condition of the first block and the distant signal
that of the second block ahead. With both at "danger77 the

Stop and Stay

Stop

Stop and Proceed

Proceed, next
Signal at Stop

Proceed

with «
Caution

Proceed tinder
ControK Prepared
to Stop Short of any
Obstructions)

FIG. 81.—Standard three-position signal aspects.
two blocks ahead are occupied and the train stops. With the
home signal at "clear" and the distant signal at "danger/7 the
first block is clear and the second occupied. The train may
enter the block under control. With both signals at "clear"
the engineer knows that two blocks ahead at least are clear and he
may enter the block at full speed. The distant signal at the
first block and the home signal of the second block are so inter-
locked that the former cannot move to "clear" until the latter